In order to establish if a printed item is authentic, visual identification techniques are commonly used. Thereto, the printed item is inspected by a (generally trained, experienced) inspector who seeks for deviations in a pattern of printing as compared to the original pattern. The inspector may seek deviations in color (in this document, the terms color and colour may be interchanged), deviations in sharpness, incorrect positions of printed objects in relation to other objects or deviations in fine patterns, such as pitch, colour and/or contrast.
A problem associated with the known method is that high quality copies may not always be recognized. In particular, when high quality equipment has been used to create copies of the printed item, the quality of the copy may be high, making it virtually impossible, even for a trained inspector, to distinguish a copy of the printed item from an original of the printed item.
The invention aims to provide an improved verification of an authenticity of the printed item.